Flameless Atomic Absorption Spectrophotometry에 의한 Cd(2)의 미량정량방법에 관한 연구

Abstract

A sensitive method for the determination of Ultramicro amounts of metal ions by the flameless atomic absorption spectrophotometry was investigated. This method was based on the direct atomization of metal-adsorbed resin suspension, but it was not adequated to cadmium which has strong volatilization. So it was attempted that stripping step on the previous method was added. As the result, Chelating resin was used NH_(4)^(+) form, and optimum pH was 4.0-6.0. Adsorption and stripping time were 15, 20 minute respectively. The calibration curve was linear up to 1.2ppb of cadmium ion concentration in the sample solution, and the relative standard deviation was 0.72% from 10 repeated measurements. In the investigation of cations effects, the alkali metals, alkali earth metal ions, Zn(Ⅱ), and Cr(Ⅲ) were not interfered in the concentration over 400 times of Cd(Ⅱ) solutions. Fe(Ⅱ), Pb(Ⅱ), Cu(Ⅱ), Ni(Ⅱ), and Mn(Ⅱ) were not interfered in the concentration up to 100 times of Cd(Ⅱ) solutions.;미량 금속을 정량할 때 종래에는 metal-adsorbed resin suspension을 직접 ghaphite furnace에 주입하여 atomic absorption spectrophotometer로 측정하는 방법을 사용하여 왔으나, cadmium과 같이 휘발성이 강한 금속에는 이 방법이 적합하지 않으므로, chelating resin을 matrix로 하여 cadmium ion을 흡착시키고 stripping한 후 상등액을 graphite furnace에 주입하여 흡광도를 측정하는 방법에 대하여 검토할 결과, 최적 pH는 4.0∼6.0이었고, 흡착에는 20분, stripping에는 15분이 충분하였으며, cadmium ion농도 1.2ppb까지 상대표준편차 0.72%로 정량할 수 있었다. 이때 cadmium ion의 흡광도에 미치는 공존금속이온의 영향은 Na(I), K(I), Ca(Ⅱ), Mg(Ⅱ), Zn(Ⅱ), Cr(Ⅲ)의 경우 cadmium ion의 400배까지, 그리고 Fe(Ⅱ), Pb(Ⅱ), Cu(Ⅱ), Ni(Ⅱ), Mn(Ⅱ)은 100배까지 영향이 없는것으로 나타났다.